A paper mill is a factory devoted to making paper from wood pulp and other ingredients using a Fourdrinier Machine or similar apparatus. It is a common misconception that paper mills are sources of odors. Pulp mills, not paper mills can be a source of malodorous air emissions.
In 105 AD, the first papermaking process was innovated in China, by the Han Dynasty Chinese court eunuch Tsai Lun in the early 2nd century AD. The technology spread from East Asia to the Islamic world after the Battle of Talas.
The earliest known paper mill is known to have operated in Baghdad, modern-day Iraq, as early as 794. After Baghdad, the paper-making process spread to Damascus, Egypt, and Morocco, and by the 10th century, it had replaced papyrus, wood, silk and parchment as the cheapest and most widespread writing medium in the Islamic world.
In Europe, the first mention of rag-paper is in the tract of Peter, abbot of Cluny (1112 - 1150 AD), while the oldest recorded document on paper in Christian Europe is the 11th century Missal of Silos, whose paper was probably made in Islamic Spain. One of the first known paper mills in Europe was in Xativa (now Jativa) near Valencia, Spain, established around 1151 AD by the Muslim Moors.
The modern paper mill uses large amounts of energy, water, and wood pulp in a highly efficient and extremely complex series of processes, using modern and sophisticated controls technology to produce a sheet of paper that can be used in incredibly diverse ways. Modern paper machines are very large and can be 500 feet (~150 m) in length, produce a sheet 400 inches (~10 m) wide, and operate at speeds of over 60 mph (100 km/h). The two main suppliers of paper machines are Metso and Voith.